The theory of binary digital frame synchronization is discussed. The effect of random data on frame synchronization is introduced. The one-pass acquisition probability expression which is related with the pattern length and construction, frame length, bit error rate, decision threshold is obtained. Finally the method of design about optimal frame format is given and the relation between efficiency of channel and acquisition probability is described.

This paper describes a method of analysing the complexity and random properties of the feed-forward sequences. Based on the method, a class of the generalized Geffe s generators is found. These generators are similar to Geffe 's generator in complexity and random properties.

The influence of ionospheric refraction on the output of interferometer is discussed and the method used to correct it is suggested. In the discussion the motion of sub-ionospheric point along the direction of declination is considered, and a new method to modify the value of f₀F₂ at sub-ionospheric point is proposed. Although these methods presented here are for correcting the ionospheric refraction of Miyun System, yet some ideas of these methods can be used in other cases.

The switched-capacitor filter is a kind of MOS large scale integrated circuit which has been developed in recent years. This paper gives an outline of the basic principle, the analytic method and the circuit structure of the switched-capacitor filter and some specific problems of integration.

The approach using the equivalent networks in the z-domain to analyze switched capa-citor networks is very attractive. This paper presents a powerful procedure. In the first place the equivalent networks are derived by applying a group of basic building blocks which are resulted under the consideration of generality and practicability. At the same time some specified transformations are proposed, with which the basic building blocks can be greatly expanded to fit in to direct use. Those transformations are also found to be useful in designing SC filters. The application of the well-known signal flow graph facilitates the derivation of discrete transfer functions. Furthermore the sensitivity of SC network can be calculated with a simple topological formula. The whole work can be done by inspection; this is the highlight.

The efficiency of output section of broadband klystron with resonant coupled cavity is calculated. In solving this problem, we use neither the time integrated electron disk model nor the space charge wave theory. The disk model requires too long computer time, and the space charge wave theory is simplistic. We propose a new modified method, with which the computer time is much saved and the calculated result is in fair coincidence with the measured one.

The effect of velocity spread on the main parameters of gyrotron oscillators is descri-bed briefly. Measures to reduce the velocity spread are discussed. A new method of measu-ring velocity spread of electrons in a cycloiding electron beam is given. By use of a high precision radial-gauge with multi-section collector, the beam transverse velocity distribution can be accurately measured. This method is characterized by the fact that the space charge effect wil not interfere with the experimental results, so the beam transversevelocity spread in a gyrotron under actual operating condition can be determined. Thus the method is superior to the "retarding-field method" and "pin-hole-camera method". A special equipment is designed for this measurement.

The developement of a high information capacity Chinese character generaor, i.e. Chinese character tube is described briefly. It is a high capacity, electron beam addressed, read only memory. Information capacity of one tube is more than one megabit. This kind of Chinese character generator has the advantage of small size, high information capacity, low cost and wide application. It can be applied to various Chinese character information processing systems.The working principle is described briefly. The experimental results of type Ⅰtube (on tube can store 512 Chinese characters with 4848 dot matrix per each Chinese characteer) are given. Finally the prospect for application and development of this kind of Chinese character tube is preliminarily estimated.

A method of digital signal processing for tracking the velocity of moving target in the application to radar system is given. The tracking accuracy of velocity of this method can be improved by the use of ZFFT. The method of ZFFT mentioned above has been proved to be valid through the experiments carried out in the computer.

In this paper, the principle of design of the shifting image section of an intensifier silicon target pick-up tube is given. An electrostatic electron-optical system with a photoca-thode having an effective diameter of 40 mm and a system magnification of 0.65 has been designed. The experiments show that when the electron image of the photocathode is tran-sfered to the silicon target, the geometrie distortion is only 2%, the field curvature is 2 mm. The astigmatism is less than 0.32 mm at 80 percent of the viewing field and the resolution is over 50 1p/mm. It shows that the design of the electron-optical system is good and reasonable.

An electron-beam-controlled CO₂ laser is simulated by computer. The calculated resu-Its are compared with the experimental data, and it shows that they are rather close. This demonsrates that the simulated calculation can give useful information about design and use of the electron-beam-controlled CO₂ laser.

A sealed off tunable CW C¹⁸O₂ laser is reported. Its water-cooled discharge tube made of quartz has an i.d. of 12 mm and a length of 1600 mm. More than 80 lines are obtained and the strongest line output is about 30W.

Applications of electron beam welding to electron devices are described. The resultsof welding are good.